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Development of the treatment system for water polluted with organic chlorine compounds by using photocatalysis in the gas-phase

气相光催化有机氯化合物污染水处理系统的开发

基本信息

批准号：
09555269
负责人：
MURABAYASHI Masayuki
金额：
$ 5.31万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Pollution of groundwater and soils with organic chlorine compounds, such as trichloroethylene and tetrachloroethylene has been serious problems, A system for the treatment of such compounds using a combination of aeration and gas-phase photocatalysis was developed in the present study. Experiments for the fundamental study to elucidate reaction mechanisms, etc. and the practical study for the development of the actual system were carried out.1. Results of the fundamental study by using a batch reactor are as follows ;1) The photocatalytic degradation of trichloroethylene (or tetrachloroethylene) was accelerated, when a TiOィイD22ィエD2 photocatalyst was pre-illuminated with UV light before the reaction. This was supposed to be due to desorption of water molecules and hydroxyl groups from the surface of the TiOィイD22ィエD2 photocatalysts.2) The second and third reactions were still accelerated, when the photocatalytic degradation reaction was repeated by using the same photocatalyst.3) Phosgene and dichloroacetylchloride were detected as the (intermediate) products. The acceleration of the repeated reactions stated above was supposed to be due to the chain reaction initiated with such compounds.4) The fundamental study on reaction mechanisms was thought to give useful information to minimize formation of harmful by-products in the continuous reactor of a pilot-plant scale.2. Results of the practical study using a system of a pilot-plant are as follows ;1) A pilot plant to treat organic chlorine compounds in the actual groundwater was constructed in success using the combination of aeration and photocatalysis. The groundwater polluted with tetrachloroethylene was well purified continuously.2) No harmful compounds over the standard were detected in the gaseous exhaust.3)The plant was operated continuously for five weeks. Practical data were obtained to show much possibility of the construction of actual larger plant.

三氯乙烯和四氯乙烯等有机氯化合物对地下水和土壤的污染是一个严重的问题，本研究开发了一种结合曝气和气相光催化处理此类化合物的系统。开展了阐明反应机理等基础研究的实验和开发实际系统的实践研究。 1．使用间歇式反应器的基础研究结果如下：1)当反应前用紫外光预先照射TiOiiD22iiD2光催化剂时，三氯乙烯（或四氯乙烯）的光催化降解加速。这被认为是由于水分子和羟基从TiOiiD22ィエD2光催化剂表面解吸所致。2)当使用相同的光催化剂重复光催化降解反应时，第二次和第三次反应仍然加速。3)检测到光气和二氯乙酰氯作为（中间）产物。上述重复反应的加速被认为是由于此类化合物引发的链式反应。4）反应机理的基础研究被认为可以提供有用的信息，以最大限度地减少中试规模的连续反应器中有害副产物的形成。2．使用中试装置系统进行的实际研究结果如下：1)成功地建立了采用曝气和光催化相结合的方法处理实际地下水中有机氯化合物的中试装置。受四氯乙烯污染的地下水持续得到良好净化。2）废气中未检出超标有害化合物。3）工厂连续运行五周。获得的实际数据表明建造实际更大工厂的可能性很大。